The present invention relates to a bread product and to a method for producing same.
Bread products, and particularly so-called "French" bread, are known to tend to get stale rapidly. If, therefore, too much bread is bought, it must either be consumed stale or be thrown away. It may possibly be reheated in the oven before being eaten, but then it dries up, is overcooked and it is hardly appetizing. Consequently, there is a tendency to buy only the quantity of bread which will be consumed in the day, in order to avoid waste, and one may find oneself short if the estimated consumption is less than the actual quantity consumed. This type of situation is often encountered by restaurant owners who never know precisely how much their clientele will consume and who, consequently, buy too much or too little bread.
It is an object of the present invention to remedy this situation and to create a bread product which keeps well, therefore which may be bought in advance for future use and to which, by a simple operation effected at the time of consumption or some time before, the appearance, consistence and flavor of a fresh bread product may be given. It will be readily appreciated that this bread product according to the invention may either replace fresh bread, or serve as a complement therefor. It is thus possible to buy the minimum of fresh bread, corresponding to the estimated minimum consumption in order to avoid waste, since, if the actual consumption is higher, the bread product according to the invention may be rapidly prepared.
U.S. Pat. No. 2,549,595, Japanese Pat. No. 6554/63 or Swiss Pat. No. 569,410 for example disclose a process of preparing bread from a traditional dough which, after the leavening phase, is subjected to a partial baking arrested after structuration but without leading to coloration and the final formation of a brown crust.
Bread of prebaked type is thus produced, which may be conserved for some time in this state and may be subjected to a final baking phase, at that moment provoking the final formation of the brown crust.
However, this bread of prebaked type can only be kept for a few days or stored in a freezer unit.
After a few days at ambient temperature, the bread of prebaked type is rapidly attacked by the sources of outside aggression, particularly by the germs in the ambient medium.
This sensitivity of the prebaked bread to the source of mould is explicable, considering that the prebaked bread having been removed from the oven before it has totally cooked, has conserved more water than totally baked bread contains; in addition, the crust formed by caramelized starch and which constitutes the envelope protecting the bread from the easy penetration of the germs, being only imperfectly formed in the case of prebaked bread, does not constitute a sufficient barrier; all the more so as the prebaked bread being very moist; the dry crust of the bread, on leaving the oven, is rapidly penetrated by the moisture inside the bread and this moist crust cannot constitute a barrier against the germs and mould coming from the outside medium.
It follows that the prebaked bread, being given its short keeping time, unless the conditions are exceptional (such as storage in a freezer unit), has met with only limited interest and has not been developed in practice.
Processes are known for conserving food products over periods of a few weeks or a few months.
In practice, the food product may be packed hermetically in vacuo or in a packing filled with an inert gas, as provided by U.S. Pat. No. 3,419,400.
This technique enables the food product to be removed from the atmospheric oxygen which constitutes in numerous cases a source of attack by oxidation of the food products leading to a stale or rancid taste. However, this technique is not adapted to the case of prebaked bread; in fact, this bread suffers from contamination by germs, mould or the like from which we find on the prebaked bread a moist, starch-based medium which forms a support particularly favorable to the proliferation of the micro-organisms, much more than from the oxidizing atmosphere of the air.
During the period of conservation, it is in fact necessary to avoid any contact between the prebaked bread and a source of contamination that may convey mould or germs on the prebaked bread.
On the other hand, it has been provided to pack bread products in envelopes which are substantially hermetic with respect to the outside medium the packing itself being subjected to a sterilization phase by heat so as to destroy the germs present on the bread and in the atmosphere inside the packing, the bread thus placed in a sterile medium being able to be kept for several weeks or months.
U.S. Pat. Nos. 3,193,389 and 3,542,568 describe a process for packaging bread products subjected to sterilization, but these patents relate to the packaging and sterilization of traditional bread which is totally baked.
Now, experience has shown that these processes, although they were suitable for packaging baked bread in a sterile atmosphere, were not adapted to the conservation of prebaked bread.
In fact, the normally baked bread has a hard crust formed by the caramelization of the outer layer of starch; this hard layer gives the bread its final structure and properties of mechanical strength; furthermore as has been indicated hereinabove, the prebaked bread contains much more water than the conventional, totally baked bread.
Due to these conditions, the prebaked bread does not withstand the operational conditions of sterilization and conservation described in U.S. Pat. Nos. 3,193,389 and 3,542,568.
According to U.S. Pat. No. 3,193,389, the bread, placed in a bag from which substantially all the air is evacuated, is subjected to sterilization at 90.degree. to 100.degree. C. for 15 mins. to 1 hr.; now, although they can be withstood by traditional, normally baked bread, these conditions are inacceptable for bread of prebaked type.
In the first place, the duration and temperature of the sterilization treatment described in U.S. Pat. No. 3,193,389, which conditions are necessary to obtain a pasteurization temperature at the heart of the bread, would provoke in the case of prebaked bread a second baking of the bread, making the prebaked bread lose its properties of prebaked bread and its possibility of reconstituting fresh bread during the final baking prior to consumption.
Above all, the maintaining of the prebaked bread, containing substantially 37% of water, at a temperature of 100.degree. for 15 minutes to 1 hour would provoke the evaporation of a large amount of the water contained in the bread and no bag could withstand the pressure thus produced. The result is that the sterilization conditions, suitable for normally baked bread, are not satisfactory for prebaked bread.
Thirdly, assuming that the prebaked bread in its package was able to withstand the severe sterilization conditions, the bread on leaving the sterilizer, would be contained in a package filled with water vapor and containing only water vapor (since the air was previously removed from the bag before the sterilization stage).
Following the cooling of this package, the water vapor condenses, which has a doubly disastrous effect on the prebaked bread.
The condensation of the water creates a moist interface between the film of the bag and the fragile and light crust of the prebaked bread; the moist medium decomposes the light crust of the prebaked bread which forms a sticky mash, the film of the bag, then sticking to the body of the bread; when the bag is opened, the moistened crust remains stuck to the film of the bag, so that the product is literally peeled like a banana, this creating conditions which are inacceptable for marketing the product.
In the second place, when the condensation of the water eliminates the inner atmosphere within the package, the latter is then subjected to the outer atmospheric pressure which is not balanced by an inner counter-pressure; this would be acceptable for a normally baked bread, having its own structure and a sufficient mechanical strength, but the prebaked bread which has only a light temporary structure does not withstand these conditions and under the atmospheric pressure collapses and loses all its shape and appearance.
The solution proposed in U.S. Pat. No. 3,193,389 and consisting in making a partial vacuum (of 0.5 to 0.5 atmosphere) (col. 7, lines 55 to 68 thereof) would not be applicable in the case of prebaked bread; in fact, the residual even partial pressure of the air would be added to the pressure of the water vapor given off during the long sterilization treatment and would certainly burst the package.
Neither is it possible to reduce the sterilization conditions according to U.S. Pat. No. 3,193,389 without limiting the effects of sterilization; in fact, this duration is necessary, taking into account the cooling of at least 6 hours and as much as 15 to 20 hours to which the bread is subjected between baking and sterilization thereof.
U.S. Pat. No. 3,542,568 describes another process of sterilization of bread in a package with a view to conserving it for a long time, wherein a succession of bags forms a continuous string communicating with one another as they pass through the sterilization chamber, thus allowing the evacuation of the heat given off during the sterilization phase towards the upstream bags; the risk of bursting of the bags in the sterilization phase is thus avoided, but this process cannot be applied to the conservation of prebaked bread.
In fact, in the package obtained according to U.S. Pat. No. 3,542,568, the inner atmosphere, on leaving the sterilization chamber and after being sealed, is constituted solely by water vapor.
In this system, the bags being in communication, the vapor given off during the sterilization phase escapes upstream and consequently repels the air present in the bags upstream, with the result that the bags arriving in the sterilization phase are impregnated with the water vapor driven from the preceding bags and which has driven out the initial air.
Under these conditions, the bag, when it is sealed, contains exclusively an atmosphere of water vapor.
The above-mentioned drawbacks are thus found again, namely the vapor, on condensing, moistens the crust and creates an adhesive interface between the envelope and the prebaked bread; in addition, condensation creates an inner vacuum and under atmospheric pressure the prebaked bread subsides. A product is thus obtained which is not commercially presentable.